Subterranean Fishes of the World

6029

2007

Illinois Natural History Survey Technical Report

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58

Ceuthophilus spp. (Orthoptera: Rhaphidophoridae) in two subgenera (Ceuthophilus and Geotettix) were examined phylogenetically, morphologically, and biogeographically in order to improve our understanding of these species that carry nutrients into caves and are thus closely tied to rare and endangered troglobites in central Texas. Crickets were collected from 43 caves across central Texas, and outgroup taxa were collected in west Texas, Kentucky, Missouri, New Mexico, and Mexico. We analyzed 1263 base pairs of mitochondrial DNA from the COI and ND5 genes and complemented this data with morphometric analyses of 19 morphological characters. Phylogenetic trees from the molecular analysis allowed us to select representatives from 25 clades for morphological work. The molecular data show relatively high levels of genetic variation and phylogeographic structure. This variation is higher than that predicted by the currently accepted species level taxonomy of Ceuthophilus. These genetically divergent lineages uncovered by our DNA sequence data may be cryptic species. Members of the subgenus Ceuthophilus are known to commonly forage outside of caves leading us to predict that they might also be better at dispersing than members of the subgenus Geotettix, which are not known to leave their caves. However, contrary to our expectations, haplotype phylograms of the two subgenera indicate that the subgenus Ceuthophilus has deeper genetic structure than the subgenus Geotettix. Therefore, Ceuthophilus populations have been isolated for a longer period than Geotettix populations. Another unexpected result is that multiple haplotypes from genetically divergent groups are found in the same cave on multiple occasions, another indicator of cryptic species. The morphological dataset included 19 discreet characters and 31 continuous characters that were used to create a morphology-based tree and plotted in a principal component analysis. The morphological and genetic trees are similar only on a rough level in that the two subgenera are generally distinct (though Geotettix is monophyletic in the genetic analysis and one morphological analysis and paraphyletic in another morphological analysis). Morphological characters are also divergent within monophyletic clades and convergent among clades, also pointing to probable undescribed species. As Ceuthophilus spp. are a key component in central Texas karst invertebrate conservation, identifying and describing any new species is a high conservation priority. Different species may have different life history patterns, foraging behaviors, and use of caves.

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